Google Imagine!

Have you ever been wasting your time to recover a website in which you have taken a picture from before? have you been looking for the name of a company or organization in which you have the Logo or Brand?
Assume you have this Logo:





and would like to know to whom it belongs? Its my favorite Linux symbol! but you are able to know it without asking me! just go to Google Imagine search engine and give this picture input, you will find all websites relating to this Logo in a second!
I took a picture from a website to put in my assignment but I forget the source! I have to find the source to make reference. Just browse in the Google Imagine and give that photo as input for search and find all relevant sites in a second!
How to convert a picture or logo on paper or on electronic file to input in a search engine??? Google Imagine